RICHARD B. HERBERT' AND BARRE WILKINSON School of Chemist~y, The University, keds LS2 9J1; UK ... AND GEORGE J. ELLAMES Department of Chemical Development, Sterling Winthrop Pharmaceuticals Research Division, Sterling Wirzthrop Research Centre, Alnwick, Northunzberla~zd NE66 2JH, UK Received July 26, 1993 This paper is dedicated to Professors Ian Spenser and David B. MacLean ... RICHARD B. HERBERT, BARRIE WILKINSON, ...